Hitherto, not only in a technical field of a semiconductor-manufacture relating device, but in various kinds of technical fields, technologies for controlling temperature for supplying a liquid whose temperature is controlled in high accuracy is developed (for example, refer to Patent Document 1).
These technologies are developed on the premise that a steadily temperature-controlled liquid is steadily supplied in approximately constant flow amount and therefore the flow amount is relatively large.
However, for example, in a case that a refractive index is adjusted by causing a liquid for adjusting a refractive index to intervene in a light path of an optical system, and the light path is moved in relation to an object in the condition, or the like, it is required that the liquid is supplied into the light path as a flow in a small amount or an intermittent flow, and in addition, it is required that the liquid is supplied in a condition of being temperature-controlled in high accuracy (for example, ±1/100° C.) so as to suppress fluctuation of the refractive index. To such a temperature control in the high accuracy of the flow in a small amount or the intermittent flow, a temperature control technology on the premise of the aforementioned large flow amount is hard to be applied in general.
Further, since the liquid to be the object of the aforementioned temperature conditioning is expensive in general, an unnecessary part of the object cannot be discarded or formed into a contaminated condition by discharging the same in a large amount. Further, even when the liquid is water, since purified water or extra-pure water separated by means of the membrane separation technology is used and the water is thereby relatively expensive resulting in high costs when discharged.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2003-86486